Machines for automatically attaching interconnecting wiring to terminals arranged on a card or panel by means of solderless wrapped connections are well known in the electronics field. The Automatic WIRE-WRAP Machine, Model 14FV, manufactured by the Gardner-Denver Company of Grand Haven, Michigan is an example of such a machine. In general, the machine consists of movable carriages containing wrapping tool assemblies and dressing fingers that are positioned to form a desired wire pattern. The automatic operation of the machine is achieved through the use of a reader which decodes the input data from a storage medium. The function of the input data is to translate the output of a computer program into the mechanical motions required of the machine to perform the wiring task.
In an actual production cycle, utility type logic card assemblies containing approximately 1100 wires distributed on two levels of a 2300 wrap post field are wired by the aforementioned type machine. Changes in the logic design, poor workmanship or other conditions often require the removal of all or part of the wiring on such cards and the rewiring thereof. Present methods, employed to accomplish the task of removing all of the wires on a utility card of the size mentioned above, may require from eight to twelve hours labor. Such present methods entail the manual unwinding of the wires from the posts by using an unwrapping tool turned by hand. Alternatively, the removal may be accomplished by using a semi-automatic wiring machine which is program-controlled to position a wrap post in line with an air operated wrap gun equipped with an unwrap tool. The tool is moved onto the selected post by the machine operator, who must also determine the necessary rotation, either clockwise or counter-clockwise, for unwrapping that particular wire wrap. Besides the labor and time required to remove the large number of wraps, an additional operation is required to reposition the field of wrap post tips to within the tolerance needed for efficient rewrapping on automatic machines. Moreover the possibility exists for irreversible damage to a wrap post during the wire removal, thereby requiring the replacement thereof--a time-consuming procedure which entails unsoldering the damaged post and soldering the new post in its place.
The unwrap assembly of the present invention is adapted to be readily installed on the automatic wiring machine which provided the initial wire wraps. In general, the machine is programmed in a sequence opposite to that of the wire installation sequence, such that desired wires are removed in an efficient manner without damage to the wrap posts.